Cartridge extractor testing machine



Feb. 1, 1949.

N. P. HOLCOMB CARTRIDGE EXTRACTOR TESTING MACHINE Filed Feb, 24, 1947ill 1 .lllll h llu I Q 3 Sheets-Sheet l Feb. I, 1949. N. P HOLCOMBCARTRIDGE pxwmcwon TESTING MACHINE, I

3' Sh'tS-Sheet 2 Filed Feb. 24, 1947 ||||l. ll llll.

N arm-and]; Holmium]:

Feb. 1, 1949. N. P. HOLCOMB CARTRIDGE EXTRACTOR TESTING MACHINE FiledFeB. 24, 194'? Patented Feb. 1, 1949 sure PATENT- GIFF'IGE MACHINENormand-T. Holcomb; Warehouse Point, Conn-.,

assigno'r to the United State's of" America as" represented ?by"theSecretary of War Application February24, 1947., Serial No. 73057712Claims: (01373 -167) (Granted under tlidact of- March 3, 1883, asamended April 30; 19283137010. G. 757) The. invention described in thefollowing specific'ation andclaims may .be. manufactured and used by orfor-the Governmentforigovernmental purposesewithout thepayment to me of:any royg alty thereon.

This invention. relates to a fatigue testing machine and moreparticularlyto a machine for testing thefatigue life ofcartridge caseextractors of firearms;

Dueto the high standards which-must be'main-- tained in modern'aut'omatic*firearms, it is es sential-thav every component ofsuch-firearmshave as highafatigue lifeems-possible? 1 To-thi's end,suitable means must be available for test ing'-th endurance of highlystressedfirearm components under conditions approximating; those-=inactual: operationi Onecomponent which must resist sudden and repeatedsti'esses is the cartridge caseextractor iir-firearms-such as the U. S.rifle;'cal; 30, M1 and the Us S. carbine, oal: .30, M1; It is obviously:a? time consuming and.expensive procedure to test thesendurance of theaboveenamed extractors by: manual oper'atiom of the firearm untilfailure occurspMoreover, since each firearm varies in its individualFoperating characteristics and since the force required to. extract" acartridgecase from the chamber increases under automatic operation; itbecomes exceedingly diflicult to obtain atrue comparison of theendurance of the extractors.

Accordingly, it'is an object ofthis invention toprovide a machine fortesting the-endurance of cartridge case extractcrsof the type found inthe U.- S. rifle, cal. .30, M1. 7

His 2. further object. of this-invention to pro-- vide a cartridgeextractor endurancetesting machine which shall 'bead-justablein order toaccommodate extractors of dilferent sizes.

It is a particular object of this intventionto provide anautomaticmachine which will compare the endurance factors of cartridge case'extractors under conditions substantially iden-- ticalto those in actualfirearm operation.

Thespecific nature of the invention-as well as: other, objects andadvantages thereof will clearly appear from a description of a preferredem bodiment as shown in the accompanying drawings in which:

Fig; 1 is a front elevationalview of -thegtesting'machine of thisinvention shown in twoparts:

Fig. 2 is a cross-sectiona1-view taken along line 2-2 in Fig. 1;

Fig. 3 is a side elevational-yiew of the testing: machine of. thisinvention-shown in: two .parts;

Fig. 4 is a cross-sectional view taken-along line- 4-4 in Fig. 1;

Fig. 5 is a cross-sectional view taken along; line 5 5 in Fig. 3;

Fig; 6 is a perspective view showingone of the: pivot arm assemblies;

Fig. 7 is a perspective view off'thle axle;

Fig. 8 is a cross-sectional. view taken'along line 88 in Fig. 1;

Fig. 9 is a perspective-view of theadaptenjandl Fig-.10 is aperspective'view of aboltiandx tractor ofthe typefound'in the-U;Sfirifle'lcali" .30, M1. v

The machine of this invention consists-lessen tially' of areciprocatin'g cylinder having a sim-* ulated firearm cartridge memberm'ountedtlier'ein and means for mounting a firearm -bolt with anextractor assembled thereto whereby th'e-ex tractor -bn such boltengages and disengages the simulated-cartridge member in "a mannerequiva lent tothe act of 'act-ual extraction of a spent cartridge casein a firearm. The actual extracting force is approximatedbyvthe:lifting-infra' weight attached-to the bolt holdingmeans; such 1weight being arranged;to be released 'priorvto' the--disengagement--ofthe extractor fr0m--the,-

cartridge member.

For purposes of-this-inventionthere is shown-- in Fig. 10 a firearm bolt|2=and'extract0r.- |=3;- theconstruction of which isparticularly. welldescribed in U. Patent No: 2,198,610 issued-to John G. Garand and neednot beamplifiedshera Sufiice-it to say-thatextractorpl3 is mountedinebolt I2 soas to allow'a curved lip Id of suchex tractor to snap by; andengage in-front of--the head. of -a firearm cartridge. Althoughthe-extractor-here shown is of the type found inthe U. -S.rifle, cal. .30, M1;it should be understood. that the invention is adapted for testinganyexetractor. resiliently mounted ina firearm bolt. in such manner asto extend. beyond the fai cefof. the. bolt.

One form of an endurance testing .machine" embodying this inventionisshown in assembled relation in Figs. 1. and 3." A vertically"disposed" frame I 5is rigidly secured by bolts oncap screws lfito abase ll whichisin turn boltedto a me table [8 or the like. Frame-I 5 isprovided with n vertically disposed dovetailed way 19in which a fixture20 is slid-210187 mounted. a

' Fixture" 20 comprises a vertical body' 2 I-' having an integral andhorizontal -upper arni- "22 and lower arm 23'. The height of body '2 idemands; of course, on the 1 size of the "firearm ibolt usedn Centrallyilocat'edand integral -with the underside 0t- 3 lower arm 23 is adownwardly projecting cylindrical portion 24 which passes through basel1 and table 18. Cylindrical portion 24 is internally threaded as shownat 9|.

A cylindrical firearm-bolt-holding member is provided with a threadedaxial shank 92 and is thereby secured within cylindrical portion 24 soas to project centrally upward through fixture arm 23. Member 25 isprovided with an integral hexagonal head 25 by means of which the heightof member 25 with respect to lower arm 23 can be readily adjusted. A setscrew 21 is provided in lower arm 23 for locking member 25 in place oncethe required adjustment of height is made. Member 25 is provided with arecess 28 adapted to receive the rear or bottom end of firearm bolt l2.

Firmly attached to the underside of table l8, preferably by bolts 93, isa U-shaped bracket 29 provided with a pair of oppositely disposedinclined camming surfaces 30 for a purpose to be explained later. Asquare opening 3| is provided through the center of bracket 29 and isflanked on. either side by a rectangular opening 32. Square opening 3|is in axial alignment with cylindrical portion 24.

A rod-like coupling member 33 is externally threaded at one end and isprovided with a head portion 36 of increased diameter at the other end.An externally threaded sleeve fits over coupling member 33 and is therearranged to be retained by head portion 36. The threaded end of coupling33 is screwed into cylindrical portion 24 and is prevented from furtherrotation by the tightening of a jam nut 34.

A weight release support member 31 extends through square opening 3| inbracket 29 and is threadably secured at one end to sleeve 35. Inefi'ect, therefore, support member 31 is secured to coupling 33 andconsequently to fixture 20. The body portion 38 of supportmember 31 issubstantially of square cross-sectional area, while the remainingportion consists of a downwardly extending shaft-like part 39, thefunction of which will be hereinafter shown. On opposite sides of body38 there is provided an integral rectangular lug 40 forming a shoulder4i for a purpose to be described.

In order to approximate the actual cartridge extracting force to whichextractor I3 is subjected in firearm operation, there is here provided aweight release assembly comprising a pair of pivoting arms 43, adisk-like weight-attaching member 44 having a pair of opposite integralupwardly extending ears 45, and a suitable solid weight 46 bolted tomember 44. Weight 46 is provided with an axial hole 41 for receivingshaftlike part 39 of support member 31.

As shown particularly well in Fig. 6, each arm 43 comprises a fork-likebody portion 49 defining a longitudinal slot 56 and what may be called aneck portion 50. Neck is of rectangular configuration and is adapted tofit through rectangular opening 32 in bracket 29 for limited horizontalmovement therein. Each car 45 of member 44 projects into slot 56 and apin 48 pivotally secures such ear to arm 43.

The lower end of slot 56 is arcuately formed as shown at 51 in Fig. 5 soas to allow pivoting movement of arm 43 against ear 45. Integral withthe back of body 49 is a substantially semi-circular lug portion 94having a suitable recess 58 therein for housing a helical spring 59against which is 4 seated at plunger 60 of such length that one endthereof normally protrudes slightly below body 49 and contactsweight-attaching member 44.

There are provided near the junction of body 49 and neck 50 a pair ofoppositely disposed shoulders 5|. A vertically disposed slot 52 isprovided in each shoulder 5| and a transverse hole 54 intersects slots52 and supports an axle 55. A roller 53 is rotatably mounted in eachslot 52 on axle 55. The periphery of roller 53 projects above shoulder51 for a purpose to be later explained.

As shown in Figs. 6 and 7, axle 55 is cylindrical at such section whereit engages transverse hole 54 but is of square cross-sectiontherebetween as shown at 6|. For purposes of securing axle 55 withinhole 54 of arm 43, there is provided at one end of the former, a head 62of increased diameter and at the other end a transverse hole 63 forreceiving a cotter pin 64 or other suitable retaining means. Head 62 isprovided with a plurality of diametrically opposed slots 95 havingarcuate bottoms. A pin 96 is fixedly secured in arm 43 and projects atright angles therefrom into one of slots 95 thereby preventing axle 55from rotating.

When arms 43 are in a normal upright vertical position, square section6| of axle 55 rests on shoulders 4| and the force of gravity acts tomaintain such engagement of weight release support 31 but as will beshown when arms 43 pivot outwardly, weight 46 becomes disengaged fromsupport 31 and is free to drop until stopped by a platform (not shown).

When the bottom of bolt I2 is properly positioned in recess 28 of member25, extractor l3 on bolt 12 extends sumciently into a suitable hole 65in upper arm 22 so that a pair of lugs 56 on bolt 12 abut the undersideof arm 22 as shown in Figs. 1 and 3. A plurality of cylindricalbolt-locating buttons 61 are provided integral with the underside of arm22 and such buttons are provided with flat inner surfaces 68 as shown inFig. 2. On the front end of arm 22 there is mounted, as by a screw 42, ablock 69 provided with a hunter screw 10, which when tightened forcesbolt l2 against the flat surfaces 68 of buttons 61. Thus bolt 12 isclamped rigidly in place.

An extension member 1| is firmly attached to the upper portion of frameI5 as by a bolt 91 and is provided with an arcuate upper bracket 12 andan arcuate lower bracket 13. Brackets 12 and 13 are each provided withan opening 14 in axial alignment with one another and are adapted toreceive a vertically reciprocating cylinder 15. A guide pin 16 isprovided in upper bracket 12 in such manner as to extend partially intoopening 14. A set screw 11 disposed in upper bracket 12 at right anglesto guide pin 16 serves to lock the latter in place.

At the lower end of cylinder 15 there is provided an annular groove 19for receiving the semicircular arms of an actuator 8|. The latter memberis bolted or otherwise fastened to any conventional crankshaft andconnecting rod arrangement (not shown) geared to a suitable power source(also not shown) whereby a vertical reciprocating movement is impartedto cylinder 15.

Cylinder 15 is provided with a helical camway 18 disposed about thesurface thereof as shown in Figs. 1 and 3. When cylinder 15 ispositioned within brackets 12 and 13, guide pin 16 engages camway 18,and as cylinder 15 reciprocates vertically a rotary movement is alsoimparted therea 3. In a machine for testing" the endurance of firearmcartridge case extractors, a' base, a frame vertically mounted on saidbase, a fixture adapted to securely clamp in testing'positiona firearmbolt with an extractor assembled thereto, said fixture slidably mountedin said frame andnormally resting on said base, said frame having aplurality of horizontally disposed arcuate'brackets, a cylinder arrangedto reciprocate vertically within said brackets and to be guided thereby,said cylinder having a helical camway cut into the surface thereof, 'aguide pin horizontally firearm cartridge case extractors, a base, aframe vertically mounted thereon, means on said frame regardless of theheight for vertically holding a firearm bolt having an extractorassembled thereto, a cylinder arranged to reciprocate vertically inaxial alignment with said bolt, said cylinder having a helical camwaycut into the surface thereof, a guide pin horizontally mounted in saidframe and arranged to enter said camway whereby rotary movement isimparted to said vertically reciprocating cylin-- der, an adapteraxially mounted in said cylinder,

and a semi-circular flange on said adapter shaped to simulate a portionof the rim of a cartridge case and arranged to engage and disen- T gagethe extractor from said adapter. a

5. In a machine for testing the endurance of firearm cartridge caseextractors, a base, a frame vertically mounted thereon, a fixtureslidably mounted in said frame for vertical movement, a

lower and an upper arm on said fixture extending horizontally andparallel to said base, a cylindrical member adjustably mounted in saidlower arm for clamping a firearm bolt and extractor in testing position,a plurality of bolt-locating buttons on the underside of said upper arm,a hunter screw adapted to retain said bolt against said bolt-locatingbuttons, a cylinder mounted in an extension of said frame above saidfixture, said cylinder having an adapter mounted thereon in axialalignment with said firearm bolt, and means for imparting a combinedvertical androtary reciprocating movement to said cylinder therebyengaging and disengaging the extractor,

from said adapter.

6. In a machine for testing the endurance of a cartridge case extractorassembled to a firearm bolt having outwardly extending lugs at theforward end thereof, a base, a frame vertically mounted thereto, afixture associated with said frame for vertical sliding movement,saidfixture having an upper arm and a lower arm extending horizontallyand parallel to said base, a cylindrical member adjustably mounted onsaid lower arm, said member having an axial recess adapted'to receivethe bottom end of the firearm bolt,--'locking means included insaid'cylindrical me'mber for retaining the latter in the position wherethe bolt lugs contact said upper arm,-a

cylinder mounted in said frame above said fixture and arranged for acombined vertical and rotary reciprocating movement, said cylinderhaving an axial bore, an adapter mounted in said bore in axial alignmentwith the firearm bolt, said'c'ylinder having a transverse holecommunicating with said bore, and means in said trans- 8- verse hole forlocking said adapter-so as to extend from "said cylinder sufficiently tobe engaged by the extractor at the end of the down stroke of the bolt.

'7. The means of claim 6 for locking said adapter in said transversehole," said means compris ing, two' tubular portions, each of saidtubular portions having an arcu'ate cut on one end thereof defining "asubstantially scmi-cylindrical groove when placed end to end with saidarcuate cuts facing each other, one of said tubular portions havinginternal threads, and a bolt inserted through said unthreaded tubularportion so as to screw into said threaded tubular portion whereby bothof said tubular portions when'positioned in said transverse hole clampsaid adapter.

8. A machine for testing the endurance of firearm cartridge caseextractors, comprising, means for vertically holding a firearm bolthaving an extractor assembled thereto, an adapter shaped to simulate acartridge head and arranged to reciprocate with 'a combined vertical androtary stroke whereby said adapter is engaged by the extractor at theend of the downward stroke and released during the upward stroke, aweight depending from said bolt holding means and arranged to be pulledupwardly along with said firearm bolt and extractor, and camming meansfor disengaging said weight and allowing it to fall free prior to therelease of said adapter from the extractor.

9. In a machine for testing the endurance of firearm cartridge caseextractors, an adapter shaped to simulate a cartridge head and arrangedto reciprocate with a combined vertical and rotary-stroke whereby saidadapter is engaged by the extractor at the end of the downward strokeand released during the upward stroke, a weight-engaging member arrangedto be pulled upwardly with said adapter on the vertical strokefiandprovided with a pair of shoul-' ders, a weight normally engaged on saidshoulders, and camming means'for disengaging said weight immediatelyafter upward movement has begun whereby said adapter is allowed tocon-'- tinue its upward movement to eventually disengage the extractortherefrom.

10. In a machine for testing the endurance of firearm cartridge caseextractors, abase having' a frame vertically'mounted thereon, a fixtureslidably mounted onsaidframe and arranged to hold 'afirearm bolt andextractor assembled thereto, an adapter shaped to simulate a cartridgecase head and arranged for vertical reciproeating movement, means forengaging said adapter with the extractor whereby said fixture is pulledupwardly away from said base and then disengaged to drop onto said base,a weightengaging member depending from said fixture, said member havingoppositely disposed rectangular lugs whereby a pair of shoulders aredefined, a, weight having pair of arms mounted thereon forpivotal'outward movement, said arms engaged with said shoulders atthebeginning of the ,upward stroke of the machine whereby said weight ispulled upwardly for a period of time, a ca'mming bracket mounted on thebottom of said base whereby said arms are caused to pivot outwardlysufiiciently to disengage with said weighteng'aging member as th'elatteris pulled upwardly, saidweight thereupon arranged to fall free back to aposition of rest,v and resilient means for pivotally re-engaging saidarms with said weight- 11. In 9, machine for testing the endurance offirearm cartridge case extractors, means for approximating the cycle ofoperation encountered in the actual extraction of a fired cartridge casefrom a firearm chamber, said means comprising, an adapter arranged toreciprocate with a combined vertical and rotary movement, asemi-circular flange on said adapter arranged to be engaged by theextractor in a first position and to be disengaged therefrom when saidadapter has rotated to a second position substantially opposite to saidfirst position, a weight having an axial recess therein, a pair of armspivotally mounted on opposite sides of said weight, an axle mountedthrough the upper portion of each of said arms, said axle having asquare mid-section and a roller mounted on either side thereof,- aweight-engaging member arranged for a partially vertical movement withsaid adapter and having oppositely disposed lugs integral therewith,said lugs having a square top surface adapted to mate with said squaremid-section of said axle and support said weight when said arms are in avertical upright position, said weight-em gaging member being providedwith a cylindrical shaft adapted to engage in said axial recess of saidweight, and a bracket having oppositely disposed inclined c'am surfaces,all adapted and arranged whereby said weight engaging member pulls saidweight upwardly until said rollers contact said cam surfaces whereuponsaid arms pivot outwardly to disengage said axle from said square topsurfaces on said weight engaging member and said weight falls free beingguided by said cylindrical shaft on said weight engaging member.

12. The resilient means of claim 10 for pivotally re-engaging said armswith said weight-engaging member, said means comprising a helical springand a plunger provided in each of said arms whereby said arms are urgedto a vertical upright position.

NORMAND P. HOLCOMB.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,409,842 Foster Mar. 14, 19222,215,958 Fullerton Sept. 24, 1940 2,350,722 Buckingham June 6, 1944

